+6Design a metrics monitoring systemSystem designCollect metrics from every host and service, store them as time series, power dashboards over months of data, and alert when thresholds are crossed.
Last asked Oct 2026
#aggregation
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Design a book price aggregatorSystem designShow the current price of a book across many online sellers, keeping prices fresh while respecting each seller's API limits.Last asked Sep 2026
+7Design a top-K popular items systemSystem designReport the K most viewed or played items over sliding windows (last minute, hour, day) from a firehose of billions of events per day.Last asked Aug 2026
Aggregate and query vehicle telemetrySystem designA fleet of vehicles reports data such as detected obstacles and vehicle metrics. Design how this data is ingested, aggregated and queried, for example counts over time and place…Last asked Aug 2026
Count keywords across a fleet's logsSystem designMany machines write logs, and you need a distributed system that gathers those logs and counts how often given keywords appear in them. The keyword set, log volume and freshness…Last asked Aug 2026
+5Design an ad click aggregation systemSystem designCount ad clicks per ad and per time window from billions of events a day, accurately enough to bill advertisers, with results available within minutes.Last asked Aug 2026
Design a driver leaderboard based on reviewsSystem designRiders review drivers after each trip. Design a leaderboard that ranks drivers by their reviews. Cover how ratings are aggregated as new reviews arrive, how rankings are stored…Last asked Jun 2026
Design an advertiser metrics tracking platformSystem designDesign a platform that tracks performance metrics for advertisers and lets them see how their campaigns are doing.Last asked May 2026- +1Design a driver location heatmapSystem designShow near-real-time density of available drivers and rider demand on a city map, updated every few seconds from millions of location pings.Last asked May 2026
Total population of a city across zip codes in SQLCodingFour tables describe geography: country, state, city and zip code, each pointing to its parent, and the population is stored per zip code. Write a query that returns the total…Last asked Feb 2026
Table aggregation with group-by sumCodingAggregate table rows with a group-by sum over a chosen column, as a database table view would. Reported on 1point3acres' Notion bank; reconstructed in our own words.Last asked Feb 2026- Car rental utilization by city (SQL)CodingGiven tables of rental cars and their rentals, write SQL that reports utilization per city: how much of the available fleet time in each city was actually rented over a period…Last asked Dec 2025
- Top 10 songs per user from listening historySystem designDesign a system that shows every user of a music service their ten most-played songs, computed from their listening history. Cover ingesting play events, the aggregation (batch…Last asked Aug 2025
- Carpool ride metrics in SQLCodingFor a ride-sharing product that lets riders share a car, write SQL over ride and request tables for a series of metrics, such as completed shared rides per day and averages per…Last asked Aug 2025
- SQL screening with joins and window functionsCodingA SQL screen covering joins, aggregation and window functions over product data. Reported on 1point3acres' Notion bank; reconstructed in our own words.
- Country with the most eventsCodingGroup product events by country and return the country with the most events. Reported on 1point3acres' Notion bank; reconstructed in our own words.
- Block type with the most childrenCodingOver a tree of typed document blocks, find which block type has the most children in total. Reported on 1point3acres' Notion bank; reconstructed in our own words.
- Percentage of blocks never editedCodingFrom block edit events, compute what share of blocks was never edited after creation. Reported on 1point3acres' Notion bank; reconstructed in our own words.
- Event type with the most eventsCodingCount product events by type and return the type with the highest count. Reported on 1point3acres' Notion bank; reconstructed in our own words.
- Most popular plan type for the top event typeCodingOver product event data, find the most common event type, then the most popular plan type among users producing it. Reported on 1point3acres' Notion bank; reconstructed in our own…